HTC Global Services L2 Engineer Interview Questions and Answers

Hash map is an internal data structure that maps keys to values. Comparator is used to compare objects for sorting.

• Hash map uses a hash function to map keys to indices in an array

• Comparator is used to compare objects for sorting in collections like TreeSet or TreeMap

• Example of hash map implementation in Java: HashMap

• Example of using a comparator in Java: Collections.sort(list, comparator)

Sample classes for Spring Boot entity, service, and controller layers with annotations

• Create entity classes with @Entity and @Id annotations

• Create service classes with @Service annotation and inject repository classes with @Autowired annotation

• Create controller classes with @RestController and @RequestMapping annotations

• Use @GetMapping, @PostMapping, @PutMapping, and @DeleteMapping annotations for HTTP methods

• Use @Requ...read more

Design patterns are reusable solutions to common software problems.

• Creational patterns: Singleton, Factory, Abstract Factory, Builder

• Structural patterns: Adapter, Bridge, Composite, Decorator, Facade, Flyweight, Proxy

• Behavioral patterns: Chain of Responsibility, Command, Interpreter, Iterator, Mediator, Memento, Observer, State, Strategy, Template Method, Visitor